Method and apparatus for processing and exploiting waste by transforming it into materials that are non-polluting and reusable

ABSTRACT

According to the invention, apparatus for processing and exploiting previously ground-up waste (1) that has had any ferrous metal content cleared therefrom and that has a water content lying in a given range, comprises a reaction chamber (21) enabling mineralizing agents to be added and to react therewith, the agents including at least an alkaline-earth hydroxide such as quicklime and an alkaline-earth salt such as calcium carbonate, reaction taking place at a temperature greater than 130° C. and less than the pyrolysis temperature of the components of the waste that are most sensitive to being decomposed by heat. Said reaction chamber (21) includes at least one continuous hopper (16) enclosing at least one Archimedes&#39; screw (15) that is rotated therein, which hopper comprises a plurality of successive chambers (22) into each of which one of said mineralizing agents is injected; said Archimedes&#39; screw (15) serving firstly to perform continuous, intimate, and uniform mixing of the particles and the mineralizing agents added thereto, and secondly to keep the grain size to less than 1 mm.

The present invention relates to a method and to apparatus forprocessing and recovering waste material by transforming it intomaterial which is non-polluting and reusable.

The technical field of the invention is that of making equipment forprocessing waste in order to avoid storing it in landfills underconditions that are more or less well controlled.

Thus, one of the main applications of the invention is processing solidor liquid waste whether of household, hospital, or industrial origin, inorder to obtain particles that are usable in various building and/orcivil engineering materials, while satisfying all non-pollution criteriaand standards for protecting people and the environment.

Numerous methods and equipments are known that attempt to solve theproblem of processing waste to avoid developing landfills which, inaddition to spoiling the appearance of the countryside, are also majorsources of pollution; waste is becoming more and more abundant, and evenstoring it in landfills is expensive.

The ever-increasing cost of this type of waste "disposal" together withthe fact that landfill sites are becoming full to overflowing, make itnecessary to find some other solution.

In the near future, industrialized countries are thus going to beconstrained to take measures that seek to protect the environment;landfills as we now know them in which residues of all kinds are allowedto accumulate will have to be phased out in favor of processing centers.

At present, 65% of waste is thus dumped without transformation inlandfills, while the remaining 45% is processed.

There are three categories of processing family, not includingcomposting which nevertheless applies to about 10% of waste but whichdoes not actually process it.

(1) Incineration which is the only method to be genuinely industrializedat present on a large scale, and which processes 35% of waste. Howeverit does not make true utilization of the waste possible, even if it ispossible to recover heat that can be used in urban or community heating:in addition, that method generates both atmospheric pollution byexhausting toxic gases, and also combustion by-products that still needto be stored and that are also dangerous, over time.

(2) Anaerobic fermentation of organic matter in liquid form, inparticular household refuse, but only a few units are presently inoperation. This method makes it possible firstly to produce amethane-rich fuel gas, and secondly to recover particulate solids which,once dried, provide fuel material, together with digested matter whichcan be used as fertilizer.

In this category, mention may be made of patent application FR 2 577 940published on Aug. 29, 1986 and patent application FR 2 551 457 publishedon Mar. 8, 1985 filed jointly by the firms UIE and VALORGA, and by Mr.DUCELLIER and Mr. PAVIA, which applications relate to methods andinstallations for degrading products, by-products, and organic wasteunder anaerobic conditions.

Unfortunately, that family of methods requires an installation that islarge (a digester or fermenter having a minimum volume of 3000 m³),which is quite complex, which needs to withstand corrosion, and whichneeds energy and additives to be fed thereto and also equipments forrecovering and storing gas; in addition, it is not possible to treat alltypes of waste therein so this type of processing is experiencingdifficulty in being developed.

(3) Accelerated mineralization by chemical reaction using quicklime,essentially to destroy organic matter, and various processing additivessuch as heating, adding other reagents, grinding, and compacting inorder to obtain a residue that is theoretically reusable.

Various types of method have been investigated in this category ofprocessing, and some constitute the subject matter of patentapplications such as FR 2 472 421 published on Jul. 3, 1981 and filed byMr. GERONIMO, FR 2 583 742 of Dec. 26, 1986, by LOMA FINANCE, and EP 427899 of May 22, 1981 by the Swiss company GOMACRIS, all three of thoseapplications mentioning Mr. BIEZ as inventor. Another relevantapplication is FR 2 612 427 of Sep. 23, 1988 by the Swiss firm CATHEL.Nevertheless none of those patent applications has given rise to genuineindustrial implementations on a significant scale, because all of thosevarious methods within the same processing family are, in fact, theresults of empirical experiments without any explanation of thechemico-physical steps that enable the result to be achieved, thedescriptions thereof tending more to recipes in alchemy than toindustrial practice; and as a result the products obtained do not havethe stated characteristics in repetitive manner and on a large scale,because:

firstly, their characteristics depend on the makeup of the wasteprocessed, with some of the patents requiring at least 30% of cellulosematter, for example, thereby putting very stringent limits on theapplication of such methods;

secondly, the proposed processes do not eliminate either ferrous and/orheavy metals or heavy metals in the form of organometallic complexes,even though they are nevertheless a major source of pollution; and

finally, the empirical nature of the experiments gives rise toimplementation difficulties, and does not enable genuine applications tobe achieved on an industrial scale.

The present invention, which is nevertheless situated in this particularprocessing category, enables methods to be implemented which are firstlywell defined since they are explained and therefore reliable andrepetitive, and which are secondly capable of providing a result thatcomplies with the required standards by using specific means and stepsthat are neither taught nor suggested in the prior art, and without itbeing necessary, for example, for the treated waste to include a minimumquantity of cellulose matter.

The problem posed is to be able to provide units for processing solid orliquid waste of household, industrial and/or inactivated hospitalorigin, and regardless of the composition thereof, for the purpose ofbeing transformed without additional polluting secondary waste orresidue into one or more products that are chemically andbacteriologically inert so that there is no need for the material comingfrom the processing to be dumped in a landfill, since the material isreusable. Such processing must enable the waste to be recovered withoutrisk of future pollution and in particular leach water from theresulting-products, must provide analyses that comply with regulationsconcerning heavy metal content in particular, and even when heavy metalsare present in the initial waste in unusually large quantity.

Another object of the present invention is to be able to run and managesuch processing units in such a manner as to remain fully in control ofoperations that are taking place in application of a method that is welldefined both technologically and chemically, that is capable of beingindustrialized, and that guarantees the above results, which processingunits must be capable of being displaced and moved on transportableplatforms in order to enable processing operations to be performed onsite where the waste is produced, thereby avoiding difficult andexpensive transport and handling operations that can give rise topollution.

A solution to the problem posed is a method of processing and recoveringwaste that has previously been ground up and cleared of any ferrousmetal parts, in which the resulting particles are checked for watercontent which is then adjusted to lie in a given range, and are thencaused to react by adding mineralizing agents, including at least onealkaline-earth metal oxide such as quicklime and an alkaline-earth metalsalt such as calcium carbonate, at a temperature exceeding 130° C. andbelow the pyrolysis temperature for the components that are mostsensitive to being degraded by heat, in which method, according to theinvention:

the particles and the reagents are continuously kneaded and ground,ensuring that the components are intimately and uniformly mixed, whilekeeping the grain size thereof below 1 mm; and

alumina and a derivative of silicic acid are added on-site to thepreceding mixture in such a manner as to create hexahydroxyl silicatecage molecules therein that capture and trap within them cations ofsmall atomic radius, such as the cations of any heavy metals that arestill present in the mixture.

In a preferred embodiment, after the waste has been cleared of anyferrous metal content, any non-ferrous metal content is eliminated bymeans of any equipment based on using eddy currents.

Also preferably, an alkali metal hydroxide, e.g. caustic soda, is addedto the particles, so as to obtain total hydrolysis of the products.

Likewise, in order to improve efficiency and to increase theeffectiveness of the mineralization reactions, the resulting particles,after the metal content has been eliminated therefrom and after thewater content has been adjusted, are preferably caused to reactsuccessively with mineralizing agents that are added to the mixture oneafter another in the following order:

an alkaline-earth metal oxide is initially added (5) to the particles,and preferably quicklime which hydrates on coming into contact with thewaste to give slaked lime:

    CaO+H.sub.2 O . . . Ca(OH).sub.2 ;

thereafter an alkaline-earth salt is added to the mixture, preferably asalt such as calcium carbonate;

alumina;

an alkali metal hydroxide, preferably such as caustic soda; and

the derivative of silicic acid, which may have acid properties such asthe chloride of silicic acid, or basic properties such as the silicateof sodium or potassium.

To achieve the object of exploiting the waste, after the particles havebeen processed chemically, they are dehydrated so as to obtain a powderand the resulting dry powder is mixed with a binder constituted by anonflammable synthetic resin that makes the particles rigid andwaterproof.

The various steps of the above method may be implemented using any knownequipment adapted for that purpose, or else with specific equipment, butgiven the way in which each of the steps is identified and thepossibility and even the recommendation that each of the steps should beperformed successively in a specific order, it is possible to useequipment that is modular and suitable for connecting in series so as toprocess waste continuously, thus obviating any need for a reactor oflarge capacity: this means that apparatus can be made that is quitecompact, mobile, and easily transported to processing sites, thussatisfying one of the objects of the present invention, and a preferredembodiment thereof is described below that satisfies the specifiedcriteria.

The result is novel methods and apparatuses for processing andexploiting waste, transforming the waste into materials that are notpolluting and that are reusable.

These methods and apparatuses overcome the various drawbacks of thepresently known equipments mentioned above, and also satisfy the definedproblems and objects.

According to the present invention, the method implemented makes itpossible to process any kind of waste, whether household waste,industrial waste, or inactivated hospital waste, without anyrestrictions on the percentages of the substances making up the waste,and that is not true for most of the patent applications that apply tothis category of processing: the invention makes it possible, inparticular, to deal with sludges that are considered as being highlypolluting, such as tanning sludge, sewage sludge, and papermakingsludge, for example.

The method of the invention may be considered as a mineralization methodmade up of a succession of complex reactions with various reagents: thecompounds that contribute to all kinds of polluting matter, whetherorganic or inorganic, are extremely varied, and the various reactionsthat are then possible between such compounds and the added reactivemineralizing agents are likewise very complex, and cannot be describedindividually. It is therefore appropriate to deal with the reactionaspect in an overall manner as described below.

The object of the invention is to process waste of any origin whatsoeverusing the same industrial equipment that is capable of adapting to thenature and the quantity of the reagents used: nevertheless, it is knownthat for a given geographical sector, the overall composition of wastecan be considered as being relatively stable; accurate analysis of thecomposition therefore makes it possible to define the operatingconditions of the apparatus of the invention prior to use, together withthe quantities and the kinds of the reagents that need to beimplemented: the invention puts no restriction on possible uses of themethod because of the respective quantities of components making up thewaste; thus, for example, the content of cellulose matter in the wasteis immaterial.

As indicated above, the method and the apparatus of the invention arecapable of being mounted on freestanding platforms so as to enableprocessing to be performed close to the sources of pollution. Processingunits may have capacities that correspond, for example, to wasteproduction of the order of 10,000 to 250,000 equivalent inhabitants, bytargeting processing at a rate of 3 to 10 (metric) tons per hour.

The products obtained at the end of processing may be used forfabricating bricks and building blocks by using a hydraulic binder or asynthetic organic binder, for preparing road surfacing material, forfilling quarries, for lightening structures, etc.

To demonstrate the absence of risk for the environment of the resultingproducts, leaching water has been analyzed, i.e. water obtained byrinsing a powder of such products as derived from waste processed by themethod implemented in the present invention, at the analysis showsprotection of a quality that bears no resemblance with that obtained bythe other method.

By way of information, the following values have been obtained byprocessing household waste from a landfill that receives garbage from anurban environment:

    ______________________________________    Total heavy metal content                       mmg/kg  Standard    ______________________________________    Cd                 0.5      10    Cu                 19      200    Ni                 37      200    Pb                 20      100    Zn                 145     1,000    Hg                 0.2      5    Cr                 45       50    ______________________________________

It should be observed that although the above results were obtainedwithout prior elimination of any pieces of non-ferrous metal, by meansof any equipment based on using eddy currents, which is nevertheless apreferred step of the method of the invention, a depollution rate isobserved lying in the range 60% to 90% relative to the initialconcentrations of heavy metals.

Other advantages of the present invention could be mentioned, but thosegiven above are already sufficient to demonstrate the novelty and theadvantages of the invention.

The following description and drawings show an embodiment of theinvention but they are not limiting in any way: other embodiments arepossible within the ambit of the scope and the extent of the presentinvention, in particular by using other means for mixing andhomogenizing the particles.

For example, without going beyond the ambit of the invention, it ispossible to envisage processing in a large-capacity vat, with apreferably horizontal moving static furnace, making it possible toperform batch processing using successive reaction steps; that wouldlose the advantage of continuous processing, that makes it possible toreduce the size of the equipment used, thus making it possible, interalia, to provide mobile and transportable processing units; in addition,in order to obtain thoroughly homogenized mixing that is also intimateand provides a small grain size, it is preferable for the equipment tobe organized as described below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagrammatic view of complete apparatus of the invention.

FIG. 2 is a simplified cross-section through an example of the reactorshown in FIG. 3.

FIG. 3 is a longitudinal section through an example of a reactor forperforming continuous processing.

Upstream from the waste processing and exploiting device 1, the wastemust initially be ground up into particles in any conventionalequipment, such as a shredder followed by a knife or hammer mill if thewaste is industrial or household waste, and if the waste is hospitalwaste then it needs to be subjected to specific additional priorprocessing to inactivate it prior to being fed to apparatus of theinvention.

For this purpose the particles of such hospital waste must be immersedin atank containing a bactericidal and viricidal disinfectant thatoperates by the surface-active effect, for example, enabling thepopulation of microorganisms, funguses, and viruses to be destroyed tonearly 100% in application of standards such as those issued by Afnor(the French standards organization), so as to be effective againstmicroorganisms, bacteria (such as NFT 72 151 and NFT 72 171), funguses(as defined in NFT 72 201), viruses (such as NFT 72 181), including theHIV1 virus; the loading hopper for such waste is preferably providedwith a shutter drawerplaced in such a manner as to ensure that it is notpossible for the operators to be splashed.

After passing through the above disinfection vat, the particles are thendried and may be injected in the same manner as waste from otherindustrial and/or household origins, into the common transformationcircuit that is described below and that serves to process it.

The first stage of the method and of processing is applied, after thewastehas been reduced to particles, and consists in removing from it ofany ferrous metal, e.g. by using a magnetic field in any known manner at2.

In addition, in order to eliminate any non-ferrous metal that is noteliminated by the preceding equipment, the apparatus of the inventionincludes, prior to the reaction chamber 21, equipment 3 based on usingeddy currents, which equipment generates microwave fields that make saidpieces of metal magnetic and therefore capable of being eliminated,which pieces of metal are amongst the items that pollute the most.

Prior to introducing the ground particles into the reaction chamber 21,themoisture content of the particles is measured and corrected ifnecessary, by using apparatus 4 for hot drying in association withmoistening means so as to obtain a water content of 10% to 40%, i.e. for1000 kg of waste fed into the reactor 21, a dry matter content lying inthe range 600 kg to900 kg, which is used as the base relative to whichthe percentages of the subsequently added mineralizing reagents arecalculated.

The reactor or reaction chamber 21 used for implementing the method ofthe invention may be described as being an elongated zone comprising acombination of a set of reaction chambers 22, e.g. as shown in FIG. 3,with each of them having a function that is essential in the running ofthe mineralization process.

As the particles are continuously moved through the elongated zone ofreactor 21, they are homogenized and cut up to obtain a grain size thatisas fine as possible, with this being done by any means 20 capable ofsimultaneously entraining the particles and grinding them smaller.

The size of the resulting particles determines the transit time theyrequire through the reactor: the smaller the particles the shorter theirtransit time since the reaction surface area is then relatively larger,and particles are processed to the core more effectively and morequickly.

The maximum acceptable grain size is 1 mm, and the preferred grain sizelies in the range 100 μm to 500 μm.

The particles are fed into the reactor 21 initially together with analkaline-earth metal oxide, such as quicklime, at a quantity that isadapted to the nature of the waste to be processed, i.e. in the range10% to 40% of the dry extract as defined above; the lime then destroysorganiccells by destructing biopolymer chains.

Thereafter, while the mixture is still in the homogenizer, an alkalineearth metal salt is added at 6, e.g. calcium or magnesium carbonate,possibly together with a small fraction of the chloride of the samealkaline earth, and preferably in such a manner as to ensure that thequantity of calcium carbonate lies in the range 5% to 10% of the drycontent, for example, while the quantity of calcium chloride lies in therange 0.025% to 0.05% of said dry extract, for example.

The above two reagents serve in combination with the quicklime toprovide good cohesion by participating in the decomposition of organicacids in order to create carbonic acids.

The use of such reagents provides numerous advantages, because:

carbon dioxide gas emission is recovered:

    CO.sub.2 +H.sub.2 O . . . H.sup.+, HCO.sub.3.sup.- +Ca(OH).sub.2 . . . CaCO.sub.3 +H.sub.2 O

when quicklime is selected as the alkaline earth; p1 nitrogen-containingemissions due to decomposition of organic matter are recovered, e.g. asfollows:

    Ca(OH).sub.2 +RNH.sub.3 Cl . . . CaCl.sub.2 +RNH.sub.3 ;

polluting and malodorous gases are eliminated with calcium sulfate beingformed:

    Ca(OH).sub.2 +SO.sub.2 . . . CaSO.sub.4, 2H.sub.2 O;

any bases present in the medium are neutralized, even though suchneutralization is secondary compared with that obtained below withsilicicacid:

    CaCl.sub.2 +H.sub.2 O . . . Ca(OH).sub.2 +MCl;

acids and anhydrides are neutralized since the oxides and halides ofalkaline earth metals such as calcium react with water to givehydroxides which constitute strong bases:

    CaCl.sub.2 +H.sub.2 O . . . Ca(OH).sub.2 +AH . . . H.sub.2 O+CaA.sub.2 ;

where the last two reactions require the addition of calcium chloride,for example, in the event that the above reaction for recoveringnitrogen-containing emissions does not produce a sufficient quantitythereof Other properties are also observed, such as sulfurization andthe formation of polysulfide, and also the dehydro-halogenation ofcertain compounds which may also be of advantage.

At this stage, it may be appropriate to add a small quantity of alumina.This additive has the effect of partially regularizing the pH of theparticles if it has become too high, however this characteristic is notessential at this stage of mineralization, since pH reduction isobtained by the addition of acid as described below. Nevertheless, inthe above conditions, by adding alumina, the resulting aluminate ion canbe at the origin of numerous complexes being formed with the aboveby-products, of which the most important is calcium sulfo-aluminate inmineral form.

Other anions such as chlorides, bromides, nitrates, manganates, andchromates are trapped to form alumina complexes: the quantity of aluminafed in for that purpose at 7 preferably lies in the range 0.1% to 0.2%by weight of the above-defined dry extract.

According to the invention, an alkali metal hydroxide such as causticsoda or caustic potash is then added to the particles in order tohydrolyse theproducts completely.

For this purpose, the particles or mixture is subjected to a temperatureof150° C. to 300° C. in the hydrolysis chamber 224, whereas in thepreceding chambers, the temperature is kept high because of theexothermal nature of the above chemical reactions, which can even makeit necessary to cool the enclosures of said chambers.

This basic hydrolysis constitutes the final stage of mineralization byhydrolysis of any organic matter such as proteins, DNA, RNA,carbohydrates, lipids, etc. that have already been partially decomposedbythe lime in the preceding reaction process.

The quantity of alkali metal hydroxide, such as caustic soda, that isaddedfor this purpose at 8 lies in the range 3% to 20% by weight of thepreviously defined dry extract.

After this mineralization, at least one acid or basic hydrolyzablederivative of silicic acid 9 is added to the mixture, e.g. silicic acidchloride at a concentration of 0.1% to 1% of the dry extract, or sodiumsilicate at a proportion of 0.1% to 0.2% together with hydrochloric acidat a proportion of 1% to 2%: these compounds react with the residualwaterand the previously added alumina present in the reaction medium toform stable silico-aluminates that are not very soluble in water. Thispropertyis due to the fact that alkali silicates generate orthosilicicacid reacting in a basic medium to give hexahydroxyl silicates in ionicform: Si(OH)₄ +20H⁻. . . Si(OH)₆ ! ⁻⁻.

This hydric structure makes it possible to capture small atomic radiusmetal cations such as Mg⁺⁺, Al⁺⁺⁺, Fe⁺⁺⁺, or cations of heavy metals.

This characteristic is essential and specific to the present inventionsince it makes it possible to trap small atomic radius cations such asthose of heavy metals still present in the mixture, and that have notalready been eliminated during prior steps 2 and 3, even though theyconstitute cations that are dangerous for the environment.

In addition, the advantage of silicic acid is that it enables the pHlevel which is generally high as mentioned above, to be brought to avalue of less than 10, and possibly even smaller depending on the typeof utilization that is intended for the product of the method; inaddition this acid is not dangerous since it is to be found everywhere,and it is therefore possible to add any desired quantity thereof: it isthus possible to adjust the quantity thereof as a function of the makeupof thewaste and of the desired pH without any problems, and excess acidmay be added to be certain of trapping all of the heavy metals.

At the outlet from the elongated zone of the reaction chamber or reactor21as defined above, the apparatus of the invention may includedehydrating equipment 11 into which the product 10 at the end ofchemical processing is fed in order to be dried therein, e.g. under avacuum and at a temperature of about 100° C.

The dried powder obtained in this way can be mixed at 12 with a binderconstituted by a non-flammable synthetic resin such as polyurethanewhich impregnates it uniformly: after such mixing, the resin mortar canbe passed through a high pressure press or an extruder type device inorder to compact the mixture including the binder, thereby ensuringcohesion andwaterproofing between the particles.

The conditions of use of products derived from waste exploited in thisway determine whether the resin is chosen because it is the cheapest,the bestat withstanding hydrolysis, the least polluting, etc. . . . .

FIGS. 2 and 3 show a particular embodiment of a reactor for performingcontinuous processing and making it possible firstly to perform theprocessing in application of the method of the invention, and secondlyto provide a physical embodiment of the apparatus shown in FIG. 1.

The reaction chamber 21 includes at least one continuous chute orelongatedreaction zone 16 containing at least one Archimedes' screw 15which is rotated by any appropriate external means 19 and which movesthe ground material along said elongated zone the chute comprising aplurality of successive, chambers 22 into each of which one of saidmineralizing As shown in FIG. 3, the portion of the Archimedes screw 15adjacent the introduction 5 to the hopper 16 and/or adjacent thebeginning of the successive chambers 22 has a different configuration,for example, the pitch of the screw, from the remainder of the screw 15so as to receive the mineralizing agents injected at 5, 6, 7, 8, and 9and admixed with theparticles in the hopper 16. The Archimedes' screw 15ensures that the particles are mixed continuously, intimately, anduniformly together with the added mineralizing reagents, and also itkeeps the grain size to less than 1 mm, and finally it conveys theparticles from the upstream inlet 5 shown on the left of the figure tothe downstream outlet 10 after it has been chemically processed, and andbeyond through the dehydrating chamber 11 and the binder-adding chamber12 as described with reference to FIG. 1 so as to obtain a product thatis reusable.

FIG. 2 is a cross-section through the apparatus of FIG. 3, showing areaction chamber 21 containing two co-rotating Archimedes' screws 15. Ineach of the chambers 22 and then the chambers 11 and 12, the Archimedes'screws are made of materials that are appropriate depending on the typeofreaction and the type of mixing specific to the added reagent.

Each of the chambers may be fitted with heating adapted to the variousrequirements, e.g. indirect heating means, such as an external thermalsystem 14 or a system 18 for an internally circulating heat-conveyingfluid which makes it possible by means of any appropriateinstrumentation 17 to monitor said temperatures and adjust them tooptimize the reaction in each of the chambers.

In the prior stage of putting such apparatus into operation, and thensubsequently while it is running, the reaction products obtainedupstream and downstream from the various chambers can be sampled toverify that thereactions are complete, as defined above, and thusenabling various proportions to be readjusted, should that be necessary,under the conditions mentioned above, so as to obtain the desiredresidue that is depolluted, stable, solid, and waterproof.

Using apparatus as described above, processing lasts for a period thatmay be estimated at a maximum of 10 minutes, and the operation of theset of equipment used, the drive of the Archimedes' screws, and theheating and/or cooling may all be performed in such a manner as to useelectrical energy only, or thermal energy or mechanical energy from anysource, or a combination of various sources of energy.

We claim:
 1. A method for processing and recovering waste which has beenground up into particles and from which ferrous metal has been removed,which comprises:determining the water content of the ground particlesand, if necessary, to achieve the following water content, adjusting thewater content to lie in a range of 10% to 40% by weight based on thetotal water content and dry content of the ground particles, introducingthe ground particles into an elongated reaction zone, adding to theground particles introduced into the elongated zone mineralizing agentsincluding at least one alkaline earth metal oxide and at least onealkaline earth metal salt, continuously moving the ground particlesadmixed with the mineralizing agents along the elongated reaction zonewhile kneading and grinding said admixture to effect an intimate mixingof the particles and the added mineralizing agents so that the particlesand agents are uniformly mixed and so as to maintain a grain size of theadmixture below 1 mm, the ground particles and mineralizing agents beingcaused to react exothermally within the elongated reaction zone at atemperature exceeding 130° C. but below the pyrolysis temperature of anycomponents in the ground waste which upon degradation would producetoxic gases so as to cause atmospheric pollution, and adding at least asilicic acid or a hydrolyzable derivative thereof in the presence ofalumina to the continuously moving admixture thus formed at a locationspaced downstream from the location of the addition of the mineralizingagents, said alumina reacting with the silicic acid or hydrolyzablederivative thereof to form stable silico-aluminates so as to createhexahydroxyl silicate cage molecules capturing and trapping thereincations selected from the group consisting of Mg⁺⁺, Al⁺⁺⁺, Fe⁺⁺⁺ andheavy metal cations present in the admixture.
 2. A method according toclaim 1, which includes eliminating non-ferrous metal remaining afterthe ferrous metal has removed by generating microwave fields so as tomake any such non-ferrous metal magnetic so as to make such non-ferrousmetal capable of being eliminated.
 3. A method according to claim 1,which includes adding an alkali metal hydroxide to the particles in theelongated confined reaction zone at a location spaced downstream fromthe location of the addition of the mineralizing agents so as to achievesubstantially total hydrolysis of products in the admixture.
 4. Aprocess according to claim 1, in which there are added to the groundparticles the following agents in the following sequence:the alkalineearth metal oxide, the alkaline earth metal salt; the alumina; thealkali metal hydroxide; and the silicic acid or derivative thereof.
 5. Amethod according to claim 1, which includes dehydrating the admixtureafter the particles have been previously reacted in the elongatedreaction zone so as to obtain a dry powder.
 6. A method according toclaim 5, which includes mixing the resulting dry powder with a binderconstituted by a non-flammable synthetic resin which makes particlesrigid and waterproof.
 7. A method according to claim 1, in which theelongated zone comprises at least one continuous hopper and contains atleast one Archimedes screw which is rotated therein so as to move theparticles along said hopper, said hopper comprising a plurality ofsuccessive chambers, wherein a given mineralizing agent is introducedinto a particular zone, said Archimedes screw serving to providecontinuous mixing so as to effect an intimate and uniform mixture of theparticles and of the added mineralizing agents and to maintain a grainsize of less than 1 mm.
 8. A method according to claim 7, wherein thereare two co-rotating Archimedes screws in said hopper.
 9. A methodaccording to claim 7, wherein the portion of the Archimedes screwadjacent the introduction to the hopper and/or adjacent the beginning ofthe successive chambers has a different configuration from the remainderof the screw so as to receive the mineralizing agents or other additivesadmixed with the particles in said hopper.
 10. A method according toclaim 1, wherein the alkaline earth metal oxide comprises quicklime. 11.A method according to claim 1, in which the alkaline earth metal saltcomprises calcium carbonate.
 12. A method according to claim 11, inwhich the alkaline earth metal salt also comprises calcium chloride. 13.A method according to claim 3, in which the alkali metal hydroxidecomprises caustic soda.
 14. A method according to claim 1, wherein therespective mineralizing agents are added successively at differentpoints along the elongated reaction zone.
 15. A method according toclaim 7, which comprises providing indirect heating means exteriorly ofor internally of the hopper to adjust the temperature within thechambers.
 16. A method according to claim 1, in which the alumina isadded in a step prior to the addition of the silicic acid or derivativethereof.